This application relates to systems and methods for controlling bowel function, particularly for patients with spinal injury or diseases of the nervous system.
There are various surgical procedures and hydraulic implants that have been developed to provide fecal continence in cases of inadequate anal sphincter strength. Electrical stimulators for the spinal cord and sacral roots have also been used to stimulate emptying of the rectum. See previously granted patents for the microstimulator implants themselves and for certain applications including therapeutic electrical stimulation (TES) to strengthen urinary and anal sphincter muscles, which are incorporated herein by reference. U.S. Pat. Nos. 5,312,439, 5,697,076, 6,061,596, 5,324,316, 5,405,367, 6,051,017, 5,193,540, and 5,193,539 incorporated by reference in their entirety.
One of the hallmarks of social animals is the ability to control when and where they relieve themselves of solid waste products of digestion as feces. The so-called xe2x80x9cbowel movementxe2x80x9d is the last step in a complex series of processes whereby food is successively processed, stored and moved along successive stages of the digestive tract. These steps are normally controlled by a complex system of smooth muscles, which are under the control of the autonomic nervous system. Humans with intact nervous systems have limited conscious awareness of these processes, but they do sense distension at the various loci in the gastrointestinal track and adjust their behavior accordingly. Distension produced by accumulation of fecal material in the rectum gives rise to the feeling that a bowel movement is imminent, permitting the person either to go to a place where it is socially acceptable to empty the bowels or to block the expulsion of feces at least temporarily by voluntarily contracting the external anal sphincter.
If the spinal cord is defective, which may result from spinal cord injury, tumors or birth defects, then various of the steps of peristaltic motion, conscious sensation, and voluntary control may be absent or abnormal. This gives rise to various problems of constipation and incontinence that interfere with the health of such patients and their ability to participate in normal social activities. Many such patients spend an inordinate amount of time each day attempting to empty their bowels by various maneuvers and in the absence of any clear indication of whether and when this is necessary or complete.
The present invention therefore provides methods and apparatus for controlling bowel function. This invention includes microminiature electronic devices implanted on or around the large bowel to sense the volume and nature of rectal contents and to stimulate peristaltic contractions to empty the large bowel when it is convenient for the patient to do so.
It is an object of the present invention to detect peristaltic motion and distension of the rectum.
It is a further object of the present invention to determine whether said rectal distension has resulted from accumulation of solid, liquid or gaseous material.
It is still a further object of the present invention to permit a patient to electrically trigger peristaltic motion upon command in order to effect defecation.
In one embodiment of the present invention, one or more microelectrical implants are injected into the walls or surgically implanted onto the serosal surface of the rectum and descending colon, where they sense motion and distension of those structures and can generate electrical impulses that stimulate peristaltic contractions. External control is also included, which transmits power and command signals to the microelectrical implants and receives sensed information from them by means of an inductive coil upon which the patient sits.